1. Field of the Invention
This invention relates to a wireless transmission system used for a self-locking lock box.
2. Description of the Prior Art
A conventional electric control door is formed with a door plank and a door frame provided around the circumference of the door plank. The door frame is bored with a locking hole and the door plank is fixed with an electronic lock box, which is mounted therein with a lock bolt corresponding to the locking hole. Thus, the lock bolt can be controlled to be inserted in the locking hole to achieve the purpose of locking, or to be moved away from the locking hole to achieve the purpose of unlocking. In addition, for supplying the electronic lock box with electric power, the door plank is usually provided with a first coil device and the door frame is correspondingly provided with a second coil device for wirelessly transmitting electric power to the electronic lock box in a way of electromagnetic induction.
However, since a space between the door plank and door frame must be retrained so that the door plank can be pivotally rotated and moved about; therefore, there will be a space between the first coil device and the second coil device and this space will considerably reduce the transmission efficiency of electric power. Further, since every time when the door is closed, the door plank more or less will produce position deviation; therefore, the first coil device cannot easily be aligned to the second coil device and this situation will also influence transmission efficiency of electric power. Therefore, observing the above-mentioned drawbacks, the inventor of this invention thinks that the conventional wireless transmission system needs to be ameliorated and hence devises this invention.